Study Says Weight Loss Is 'Contagious'

Much of the theatricality associated with the televised weight loss competition, "The Biggest Loser" can make its contestants' weight loss seem as impossibly dramatic as the rest of the reality show. But according to the latest research from Brown University, competitive, team-based weight loss competitions can be very effective.

Publishing in the journal, Obesity, researchers from the Miriam Hospital's Weight Control and Diabetes Research Center and The Warren Alpert Medical School observed participants in Shape Up Rhode Island (SURI) -- a 12-week, statewide online weight loss competition in 2009 that was designed by Dr. Rajiv Kumar, a co-author of the study.

Participants joined as part of a team and then competed against other teams in three categories: weight loss, physical activity levels and pedometer steps (another measure of activity). In total, 3,330 state residents with body mass indexes of 31.2 or greater participated in groups of five to 11 people on a total of 987 teams. Researchers found that people experienced similar weight loss levels as their teammates. They also found that team members who said they were inspired by teammates lost more weight than those who didn't attribute influence to their team. Overall, those who lost a clinically significant amount of weight -- defined as five percent of their initial body weight or more -- were clustered on the same teams.

“We know that obesity can be socially contagious, but now we know that social networks play a significant role in weight loss as well, particularly team-based weight loss competitions,” lead author Tricia Leahey said in a statement. “In our study, weight loss clearly clustered within teams, which suggests that teammates influenced each other, perhaps by providing accountability, setting expectations of weight loss, and providing encouragement and support.”

That finding wraps nicely into the mounting data that shows a connection between social networks and health behaviors -- particularly things like diet and exercise.
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